Potato cod (Epinephelus tukula)
|Also known as:||grouper, potato bass, potato grouper, potato rockcod, sumeyn|
|Size||Length: up to 1.5 m (2)|
- The potato cod is identified by the large, potato-like dark blotches on its body.
- The potato cod gets its scientific name Epinephelus from the Latin word meaning ‘clouded over’, and tukula for ‘maneater’, which refers to its ferocity.
- In captivity, the potato cod is capable of changing colour, appearing to turn its spots ‘on and off’, according to the colour of its surroundings.
- Not afraid to approach people, the potato cod is a bold fish, often becoming a nuisance by tampering with divers’ kit.
The potato cod is classified as Least Concern on the IUCN Red List (1).
A large and robust fish species (3), the potato cod (Epinephelus tukula) has a light brownish-grey body, with dark brown to black widely-spaced blotches (2). Small dark spots are present on its head, as well as irregular streaks that mainly radiate from its eyes (2) (4). The fins have prominent spines and small dark spots (3), and the caudal fin is more rounded in young than in adults. The potato cod has 11 spines running along its back (2), as well as 3 spines on its rear (4). Its large mouth contains canines and several rows of backward-folding teeth (3).
In the water, the potato cod’s body appears lighter and the dark blotches more conspicuous. When captured, this species takes on a darker colouration and the blotches become far less obvious (5).
The potato cod is widely distributed across the Indo-Pacific (1), from the Red Sea and East Africa, southern Oman, Pakistan, and the Gulf of Aden to southwest India, Australia, Taiwan and southern Japan (4). Within Australia, the potato cod is found on and to the north of the Ningaloo Reef in Western Australia, as well as throughout the Great Barrier Reef to Queensland (5).
Inhabiting rocky and coral reefs (3), juvenile potato cod survive in tidal pools, whereas the adult fish are found at depths of 10 to 105 metres (6).
Relatively little is known about the major life history characteristics of the potato cod (3) (7), also known as the potato grouper (1). However, grouper fish in general share many life history traits that may be relevant to this species. Grouper fish habitually spawn offshore, on sea shelves approximately 30 metres deep, or up to 70 metres deep at the edge of coral reefs. Pelagic larvae are transported from spawning sites to inshore nursery grounds where they then settle as juveniles. Later in the life cycle juveniles join adult populations offshore where they move between different habitats (8).
Grouper fish are slow to mature, spawn in groups and exhibit irreversible sex change under certain conditions (8). Potato cods reach maturity at lengths of around 90 centimetres (3) (6), and although most adult fish are solitary, courtship displays and pairing occur during the breeding season (3).
The potato cod’s diet consists of a variety of reef fish, crabs, crayfish and skates. This species ambushes its prey, which it generally then captures following a short chase. It is an aggressive and territorial species that is known for its highly inquisitive behaviour. The potato cod is often a nuisance to divers due to its tendency to approach and tamper with their gear and catch. Its large size and behaviour make this species a dominant predator within its habitat (3).
Potato cod often encourage cleaner wrasse (Labroides species) to feed on parasites that become attached to their scales (9).
Due to its inquisitive nature and the fact that it inhabits shallow water, the potato cod is vulnerable to over-exploitation, particularly from spear fishing. Potato cod were once seen as trophy catch for divers, and although this is no longer the case this species is still often caught by anglers despite its protection by law (3).
The potato cod is a protected species throughout most of its range in Australia (5), and has responded well to marine park protection (3). Offshore coral reefs are essential to the survival of the species, and therefore it is important that the proposed regulations of the Queensland Fisheries Service are enforced to maintain wild stocks of the potato cod. These enforcements include a cap on the number of fish that can be caught and restrictions on the size of fish authorised for capture, with minimum and maximum size limits in place (10). Spear fishing of potato cod is illegal in South Africa (11).
Find out more about the potato cod:
Queensland Government Department of Agriculture, Fisheries and Forestry - Potato rockcod:
The Australian Museum - Potato rockcod:
Fishbase - Epinephelus tukula:
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- Caudal fin: the tail fin of a fish.
- Larva: immature stage in an animal’s lifecycle, after it hatches from an egg and before it changes into the adult form. Larvae are typically very different in appearance to adults; they are able to feed and move around but are usually unable to reproduce.
- Parasite: an organism that derives its food from, and lives in or on, another living organism at the host’s expense.
- Pelagic: relating to or inhabiting the open ocean.
- Spawning: the production or depositing of eggs in water.
- Territorial: describes an animal, a pair of animals or a group that occupies and defends an area.
IUCN Red List (November, 2012)
- Food and Agriculture Organization of the United Nations (1996) The Living Marine Resources of Somalia. Food and Agricultural Organization, Rome.
- Van der Elst, R. and Borchert, P. (1993) A Guide to the Common Sea Fishes of Southern Africa. Struik Publishers, Cape Town.
- Randall, J. (1995) Coastal Fishes of Oman. University of Hawai’i Press, Honolulu, Hawai’i.
- Prokop, F. (2006) Australian Fish Guide. Australian Fishing Network, Bayswater, Australia.
- Yeh, S.L. et al. (2003) Induced sex change, spawning and larviculture of potato grouper, Epinephelus tukula. Aquaculture, 228: 371-381.
- Grandcourt, E. (2005) Demographic characteristics of selected Epinepheline groupers (family: Serranidae; subfamily: Epinephelinae) from Aldabra Atoll, Seychelles. Atoll Research Bulletin, 539: 199-216.
The Florida State University Coleman and Koenig Laboratory - Grouper Ecology (November, 2012)
- Cooke, F. and Bruce, J. (2004) The Encyclopedia of Animals: A Complete Visual Guide. University of California Press, Berkeley.
- Pogonoski, J., Pollard, D. and Paxton, J. (2002) Conservation Overview and Action Plan for Australian Threatened and Potentially Threatened Marine and Estuarine Fishes. Environment Australia, Canberra, Australia.
- Heemstra, P. and Heemstra, E. (2004) Coastal Fishes of Southern Africa. NISC, Grahamstown, South Africa.